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(N0 Mo deL') E. M. HAMILTON.

POLE CHANGER.

No. 379,062. Patented Mar. 6, 1888.

wiznesses:

, all? UNITED STATES PATENT OFFICE.

. EMERY M. HAMILTON, OF NEW YORK, N. Y.

POLE-CHANGER.

SPECIFICATION forming part of Letters Patent No. 379,062, dated March 6, 1888.

Application filed September 3, 1886. Serial No. 212,590. (No model.)

To all whom it may concern:

Be it known that I, EMERY M. HAMILTON,

of the city, county, and State of New York,

and a citizen of the United States, have invented an Improved GontinuityPole Changer for Telegraphs, of which the following is a full, clear, and exact description, reference being bad to the accompanying drawings, forming part of this specification.

My invention relates to a telegraph-instrument known as a continuity pole-changer, for use in duplex, multiplex, and quadruplex telegraphs in reversing the direction or chang ing the poles of the electric current; and my invention consists in the devices hereinafter described,and arranged to operate as set forth, and as more at length recited in the claims.

Figure 1 is a front end elevation of a telegraph-instrument containing my invention. Fig. 2 is a side elevation of the same; and Fig. 3 is a detached elevation in detail, partly in section, of the improved retracting-spring I employ in connection with the vibratory ar mature-lever of a telegraph-instrument.

A is the magnet.

Bis the armature, and B the armature-lever, pivoted at b;

G and O are yielding or spring-actuated contact-levers, which are operated by the armature-lever B to accomplish the reversal of the current or pole-changing.

D and D are rigid arms carrying contactpoints d d, respectively, by means of which the closing or continuity of the circuit is secured during the time that the pole-changing is being accomplished.

The structure, operation, and function of this instrument being well known, a detailed description thereof is unnecessary.

My present invention relates particularly to the rigid motion-limiting stops E E; and the object of my invention is to prevent the jumping or flying back of the yielding contact-levers O 0 when either of them is struck by thearmature-lever B in making contact, while at the same time the limiting of the movement of the armature-lever itself is accomplished.

The armature-lever, as shown, carries the contact-points b and b on opposite sides, and these points are arranged for contact with the contact-points a and 0, carried, respectively,

by the yielding pole-changing levers G and C. I arrange the rigid motion-limiting stops E and E to impinge or bear upon the levers O and C, respectively, on the sides thereof opposite to the sides which have contact with the armature-lever. These stops E and E are adjustable toward and from the said levers, respectively, preferably by being in the form of a thumb-screw working in a threaded orifice in a lug, e e, on the instrument-frame, and to give them the rigidity or fixed adjustability desired these screws have check-nuts e and 6 respectively, as shown.

It is evident that by means of these stops E E, located relatively to the yielding contactlevers and the armature-lever as described, while the armature-lever is adj ustably limited in its vibrations, the yielding contact-levers will be prevented from jumping or flying back in consequence of the blow when struck by the armature-lever. In the absence of these stops, as described, the tendency of the levers O or O',when struck by the armature-lever in its vibrations,is to be thrown upward and downward, respectively, away from the armaturelever, and thus to break or disturb the nature of the contact between the points carried by the said levers. Such breaking or disturbance of the contact is objectionable, in that it is liable in the former case to cause a burning or injury to the contact-points, and in the latter case to produce variations or vibrations in the current.

I prefer to construct and mount the yielding contact-levers O and O as shown in the drawings-namely, by attaching to the pivotal end of each a leaf-spring, c, and providing a post, ciwhich is screw-seated in the frame and which carries a shoulder or lug, c, on its end and on the side diametrically opposite to that from which thelever extends, and seating said spring in a slot cut in said shoulder or lug, as shown. The seated end of the spring 0 is thus located on the diametrically-opposite side of the pivotal post 0 to that from which the lever extends, and consequently this seated end may be carried or drawn upward or downward by turning the post in its seat to give an increased tension to the spring in either direction without at the same time correspondingly canting the lever itself upward or downward. This is desirable,-in that the levers may have their spring-governing tension varied without substantial alteration of the position of their contact-bearing ends relatively to the armaturelever.

F is the retracting-spring of the armaturelever. This spring is in the form of a spiral coil, and at one end it is seated and bears in a recess, f, in the armature-lever,while at its 0pposite end it bears against the head f of asetscrew, f, which passes longitudinally of the spring and through a slot, 12 in the armaturelever, and works in a threaded seat in a lug or support, f, located thus on that side of the armature which is diametrically opposite to the side thereof on which the spring bears. By means of this arrangement the spring is capable of being adjustably compressed between the armature-lever and the head of the setserew, and thus the action of the spring on the armature is that ofa pushing-spring in contradistinction to a pulling-spring. When pulling-springs are employed in connection with armature-levers, the elongation or flexing of the spring-spiral causes a vibration of the spring-wire during the operation of the instrui'nent, which produces a singing tone that is liable to interfere with the effective and satisfactory use of the instrument by the operator. By means of the pushing-spring, constructed and arranged as described, I produce a spring which is entirely silent, being free from vibrations, and thus producing no singing tones while the instrument is operated. It is evident, moreover, that this improved retractingspring is adapted for use generallyin telegraphinstruments, in combination with a vibratory armature-leverworkingbetweencontaetpoints 0r stops.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a continuity pole changer for telegraphs, the combination, with the vibratory armature-lever and the yielding pole-changing levers, of adjustable stops located one on the side of each of said pole-changing levers which is opposite to the side of said lever having contact with the armature-lever,whereby, while the motion of the armature-lever is adjustably limited, the pole-changing levers are prevented from breaking or disturbing their contact with said armaturelever when struck thereby in its vibrations, as and for the purpose sct forth.

2. In a telegraphinstrument, the combination, with the vibratory armature-lever working between motion-limiting stops and slotted at I), of the retracting-spring F, the set-screw f which passes longitudinally through said spring and has the head f, between which and one side of said lever said spring bears, and a lug or support, f, located on the side of the lever diametrically opposite to that side upon which said spring bears and to which said setscrew extends through said slot in said lever and in which said screw works in a threaded seat formed therein, substantially as described.

EMERY M. HAMILTON.

WVitnesses:

A. S. FITCH, HENRY EICHLING. 

